Method of maintaining open-hearth-furnace walls



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Nom 24,1925.' .1,563,038 y s. NAlsMn'u-u l METHOD oF mmmmme P'EN HEARTH mamon wALLs.

Malawi/ Nov. 24,1925; 1563938 S. NAISMITH METHOD OF MAINTAINING-OPEN HEARTH' FURNACE WALLS v Filed-Nov'. 10. 1924 4 S'heextsa-Sluaei'. 2

. 1,563,038 NAnsMm-a METHOD OF MAINTINING OPEN HEARTH FURNACE WALLS Nov. 24- 1925'.

FiledNov, 10. 1924 4 Sheets-Sheet 5 Novo 24' S. NAISMITH METHOD OF MAINTAINING OPEN HEARTH FURNACE WALLS' l Film Nw'. 1o. 1924 4 sheets-sheet 4 Patented Nov. 24, 1925*.

UNITED STATES PATENT OFFICE;

l SAMUEL NAISMITH, OF CHICAGO, ILLINOIS,v ASSIGNOR TAO OPEN HEAR'IHl COMBUS- TION' COMPANY, 0F CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE.

4nrn'rrron on MAINTAINING. OPEN-HEABTH-FURNACE WALLS.

Application filed November 10, 1924. Serial No. 748,963.

To all lwhom t may concern.' l Be it known that I, SAMUEL NAIsMrrH, a citizen of the United States, residing at Chlj cago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Methods of Maintaining Open-Hearth-Furnace Walls, of which the following is a specification.

This invention relates to a new and im- 110 proved method of maintaining open hearth furnacel walls, and more particularly to a construction of such walls whereby they may be protected by vfurnace lining material.

'l5 .Open hearth furnaces as generally constructed comprise vertically extendingl front and back walls which are ,made ofsiliceous brick. These walls are subjected to the very high temperature of the lfurnace and f2 to the basic conditions of the melting chamber and are comparatively rapidly destroyed. Their replacement requires the shutting down of the furnace withV consequent loss in operating time as well as the 5 actual expense of the replacement. v

The furnace bottom is lined with refractory materials in. loose form suchas dolomite. Due to the angle of repose of this loose material, itI is not possible to protect the vertically extending walls with it without unduly restricting the hearth area availableA for the bath. With an ordinary furnace construction the furnace bottom 'can be built up the height of the back .wall 'only Il 'slightly above the door sill elevation. v It'is. an object ofthe present invention to provide a meanswhereby the furnace back "or front walls or both may be protected by 'a layer of lining material. v

It is a further object to provide an open Shearth construction wherein the front or back walls or both are adapted to retain thereon a' layer of .refractory material. i It is'an additional `object to provide a constructionfnf this character which is simple v ,in vd.esig1i"jan d which may be applied to existing 'installationswithout*4 material altera- 'tion therein. Other land further objects will appear as the description proceeds. I

I have illustrated 4certain preferred 4embodiments of my construction in the accompanying drawings in which-Q` Figure 1 is a vertical section taken thro-ugh a furnace constructed according to my invention, v

Figure 2 is a view similar to Figure 1 but showing a modified form of construction.` l 4Figure 3 is a view similar to Figure 1,`

showing a further modification and Figure 4 is va horizontal section of one half of a4 furnace taken just under the roof in tllle form of construction shown in Figure Referring rst to the form of construction shown in-Figures l and 4, the furnace com- 5 prises the hearth support 11 from which the furnace is supported upon beams 12.

The hearth bottom 13 is formed of basic brick and the furnace bottom proper 14 is formed of dolomite or magnesite. The furnace `isshown supplied vwith the tapping hole 15 and the tapping hole plate '16.,1 i Theends of the furnace may be ofan'y usual form and asshown in Figure 4,'the

end'is provided withthe gas uptake 17 and ,'the'air uptakes 18. The port 19 discharges into the furnace chamber. The sidewalls 20 of the ends of the furnace are vertical and are supported by the vertically extending buckstays 21. The wall 'of the intermediate portion of the furnace, or the front and back walls of the hearth are supported 5 vby the buckstays 22. The lower portions of these buckstays extend in the same vertical plane as the lower portions of the buckstays 21. The buckstays 22 are provided with intermediate outwardly and upwardly sloping portions 23 and with vertically ex-` tending u per portions 24 which are located 'in vertica -planes outwardly of the buckstays 21. The charging floor has been shown at 25 and the platform in the back 0f the furnace is shown at 26. 'The upper'endsof the buckstays are 'oined by usual types of binding channels 2 The furnace doors 28 are loperated by mechanism comprlsijng4 chains 29 and pulleys 3 0. The arched furnace roofl 31' is supported at its sides upon the skewback channels3\2 and 33.

The front wall is formed of brick 34, so placed as to carry the Wall up at an angle corresponding to the angle of the supporting buckstays. The back Wall 35 is similarly sloped and is shown provided with the water cooled support and cooler 36. The wall also contains the back slag line cooler 37. The front wall 34 is provided with water cooled supports and coolers 38.

As clearly shown in Figure 1 the furnace bottom lining of dolomite or magnesite 14 extends upwardly at 39 upon the front wall to the point of junction of the wall apd roof; similarly at 40, the lining-extends up on the back wall 35. The angle of the front and back walls are such as to insure their retaining their covering of the lining material. rIhe angle of the Walls must therefore be not materially less than the angle of repose of the lining material. The angle will vary with the angle of repose of the material used for lining the furnace. Where the material is put on loose the angle will be greater than where the material is l i put on in plastic condition, as has heretofore been customary in some furnaces. By making the Walls upon such anangle they will remain covered without the necessity for such a thickness of lining material at the slag line, as will restrict the normal hearth area.

rIhe form of construction shown in Figure 2 is generally similar to that just described. The hearth buckstays 50 are provided with their entire lower portions 51, extending upon an angle. rlhe front breast plate 52 and the tapping hole plate 53 extend upon a similar angle. There is no diminutionl of the width of the furnace at the slag line and the bottom of the furnace is of the usual capacity. The sloping front wall 54: is covered by the dolomite, or other-lining material 55. The rear wall 56 is similarly covered' by layer 57 of the refractory materia] and the wall is shown as providedw`-` a with the water cooled and coolers 58.

In the form of construction shown in Figure 3 the furnace is provided with the front breast plate 61 extending outwardly upon such an angle that the front hearth buckstays 62 are supported upon the plate 61 and extend in a plate located outwardly from that of the furnace end buckstays 63.

supports .The back wall 66 is formed with its outer .face 67 extending'. vertically against the buckstays while its vinner face 68 is formed upon such an' angle as to support the layer of lining material 69. The back wall 66 is shown provided with the cooler 70. rl`he front wall 71 is shown as constructed in the manner similar to the back wall 66. In the form' of construction shown in Figure 3, the front Mld back Walls are selfcoo ed supports and coolers which are necessary in the forms of construction shown in the otherflgures.

Any of the forms of construction shown permits the front and back walls tov be covered by the protective refractory lining. This is accomplished without restricting the hearth area and without the necessity for the modification, or the reconstruction of the greater portion of the furnace structure. While the invention has been shown as applied to both front and back walls, it may be used for only the back wall if desired.

While I have shown certain preferred forms of construction by way of illustration, it is to be understood that I contemplate such changes and modifications as come within the spirit and scope of the appended claims.

I claim:

1. In an open hearth furnace or the like, a back wall inelining upwardly and outwardly throughout its extent at such an angle that the furnace lining material will lie on the wall surface and a furnace lining extending up said inclined wall substantially 151i* at such an angle that the bottom lining may extend up the sloping wall to the roof and be retained in position due to the'normal angle of repose of the material without constriction of the hearth area.

3. In an open hearth furnace, a hearth and furnace ends of normal width, front and back walls sloping upwardly and outwardly from the sides of the furnace hearth, loose furnace lining material covering said walls, and a roof for the furnace of normal width at the ends and broadened over the hearth to meet the 'tops of the outwardly sloping walls.

4. In an open hearth furnace or the like, back wall above the metal line inclining outwardly toward the roof and beyond the normal wall line, the furnace hearth being normal in width, and a covering of refractory material extending up and lying on said sloping wall.

5. In an open hearth furnace o); the like,r

mit

tendingup and lying on said inclined porheight being minimized by the downward tion. curveJ of the roof and being less than the 7. In'an open. hearth furnace or the like, height of a vertical wall erected :it the same l0 a wall having its uner portion inclined point. y 6 outwardly and upwar y at such an angle as Signed at Chicago, Illinois, this 3rd day to retain a covering of refractorymaterial, of November, 1924. and a roof curved in 'cross section, the Wall SAMUEL NAISMITH. 

